The present invention refers to a meter, and in particular to a meter which can be used with metering aerosol devices as for instance inhalers or atomizers.
There are known various metering aerosol devices for inhalation purposes which dispense an amount of medicament or drug of an exact dose in the form of a mist or an aerosol for instance for the treatment of respiratory tract diseases. Here, above all, the reliable metering of the dispensed medicament is important so that a specific therapeutical effect for the patient can be achieved. Such metering aerosol devices are for instance the so-called MDI (metered-dose inhalers) which normally have a container for accommodating a liquid or powdery medicament, a suitably designed nozzle for atomizing and distributing the medicament, and an actuating device with a mouthpiece via which the generated medicament-containing aerosol is inhaled. In case of propellant aerosols, the actuation of the metering aerosol devices is effected for instance in such a way that the medicament container is displaced linearly with respect to the nozzle arranged in the actuating device, whereby a defined amount of the atomization material is released. A metering aerosol device of said kind is described for example in EP 0 254 391.
Metering aerosol devices usually are designed for multiple dosages. In this connection it is desirable that the number of the dispensed doses, in other words of the dispensed spraying puffs, or of the still available spraying puffs is indicated to the user in order to guarantee that the patient is informed at an early point of time of the fact that the medicament is consumed. Thereby it is avoided that a patient carries with him or her an already almost empty metering aerosol device for instance as a prophylaxis of an acute asthmatic attack.
Therefore controlled-dosage atomizers or controlled-dosage inhalers have been provided with different meters or counters. For instance in EP 0 254 391 there is described an inhaler with a flat meter which is formed on the side of an aerosol dispenser facing the patient. From EP 0 505 321 there is known a reusable inhaler with a resettable meter which is incremented when the first relative position of storage chamber and metering pin is reached. The meter disclosed in GB 1 317 315 has a plurality of annular elements which cooperate mechanically in order to indicate at an indicator ring the dosages still available. Further medicament dispensers with a mechanical meter are disclosed for instance in WO 86/02275 and WO 93/24167.
The known meters for metering devices, however, have either a complex, unmanageable structure or require rather considerable modifications of an already existing metering aerosol device to enable the use thereof together with a meter. But such a modification of an already existing metering device is disadvantageous in that after-wards said device has once again to be subjected to an official approval procedure and the tests involved therewith regarding the medical applicability. This, however, usually is a tedious and expensive process and therefore is undesirable.
Moreover, the known meters are expensive and therefore are not suitable for the mass production of a product which, otherwise, can be manufactured at low costs.
Consequently, proceeding from prior art, the object of the present invention is to develop a meter with small dimensions which has a simple and therefore low-cost design and which can be used with different inhalers for counting the dosages without substantial modifications having to be carried out at the inhalers.
This object is solved according to the invention by a meter comprising four disk units which are arranged in parallel to each other, the centers of which are located on an axis extending perpendicularly to the planes of the four disk units, and a first disk unit of which has first receiving means for taking up a force effecting a rotation of the first disk unit around the axis and first transmission means for the transmission of the motion of rotation onto a second disk unit which includes second receiving means for taking up a force being transmitted by the first transmission means and effecting a rotation of the second disk unit around the axis and second transmission means for transmitting the rotation onto a fourth disk unit which includes third receiving means for taking up a force transmitted through the second transmission means and effecting a rotation of the fourth disk unit around the axis.
Advantageously, the third disk unit defines a fixed position with respect to which the first, second and fourth disk units are mounted rotatably.
In one embodiment the first receiving means of the first disk unit are an external toothing. Furthermore, the first transmission means and the second receiving means are realized in the form of a fixed connection between the first and the second disk unit.
In said embodiment the second transmission means is realized in the form of a spring cam which is arranged elastically at the outer contour of the second disk unit, and the third receiving means is realized in the form of an internal toothing at the fourth disk unit.
To the end that the spring cam comes into engagement with the internal toothing of the fourth disk unit, at the outer contour of the third disk unit at least one projecting part is provided which in a predetermined rotational position of the second disk unit relative to the third disk unit deviates the spring cam in radial direction.
In an advantageous development, the spring cam is wedge-shaped, and the width of the spring cam is larger than the thickness of the second disk unit so that the spring cam projects over the second disk unit in the direction of the axis.
In order to avoid an unintentional reset of the meter, the fourth disk unit has a second toothing circularly formed around the central point of the fourth disk unit, and the third disk unit has a plurality of snap-in toothings for the engagement into the second toothing of the fourth disk unit.
Advantageously, the radius of the second disk unit is larger than the radius of the first disk unit, the radius of the third disk unit is larger than the radius of the first disk unit and smaller than the radius of the second disk unit, and the radius of the fourth disk unit is larger than the radius of the first, the second and the third disk units.
For mounting the four disk units, a bearing pin is provided in a preferred embodiment which has a first section for slidably mounting the first and second disk unit and a second section for slidably mounting the fourth disk unit, and at which the third disk unit is secured between the first and second section.
The bearing pin is used preferably also for securing the meter at an object, for instance an inhaler or metering aerosol generator, and for this purpose the bearing pin has a third section which, on the side of the first disk unit, extends out of the meter.
In order to prevent an unintended reset, the second disk unit has an internal toothing. As counterparts, at the bearing pin there are arranged preferably L-shaped locking elements which interact with the internal toothing of the second disk unit.
In a particularly advantageous development, the meter comprises four disk units which are arranged in parallel to each other, the center points of which are located on an axis extending perpendicularly to the planes of the four disk units. A first disk unit has first receiving means for taking up a force effecting a rotation of the first disk unit around the axis and first transmission means for transmitting the rotation onto a second disk unit. The second disk unit has second receiving means for taking up a force transmitted by the first transmission means and effecting a rotational movement of the second disk unit around the axis. Furthermore, the second disk unit has a spring cam which is arranged elastically at the outer contour of the second disk unit for the transmission of the rotation onto a fourth disk unit which in turn has an internal toothing for taking up a force transmitted through the spring cam and effecting a rotation of the fourth disk unit around the axis. Here, at the outer contour of a third disk unit, there is provided at least one projecting part which in a predetermined rotational position of the second disk unit relative to the third disk unit deviates the spring cam in radial direction so that the spring cam comes into engagement with the internal toothing of the fourth disk unit, wherein at least one tooth of the internal toothing of the fourth disk unit is filled up in order to lead to a locking effect. The advantages of said development will be described in the description of the embodiments.
In an alternative development which, however, is also especially advantageous, the meter includes four disk units which are arranged in parallel to each other, the centers of which are located on an axis extending perpendicularly to the planes of the four disk units. A first disk unit has first receiving means for taking up a force effecting a rotation of the first disk unit around the axis and first transmission means for transmitting the rotation onto a second disk unit. The second disk unit has second receiving means for taking up a force transmitted by the first transmission means and effecting a rotation of the second disk unit around the axis. Furthermore, the second disk unit has a spring cam which is arranged elastically at the outer contour of the second disk unit for the transmission of the rotation onto a fourth disk unit which in turn has an internal toothing for taking up a force transmitted by the spring cam and effecting a rotation of the fourth disk unit around the axis. Here at the outer contour of a third disk unit there is provided at least one projecting part which in a predetermined rotational position of the second disk unit relative to the third disk unit deviates the spring cam in radial direction so that the spring cam comes into engagement with the internal toothing of the fourth disk unit, wherein at least one tooth of the internal toothing of the fourth disk unit is removed in order to suppress an engagement of the spring cam. The advantages of said development will be described in the description of the embodiments.
The inventive meter of the above-described kind is especially used in inhalers, atomizers or similar metering aerosol devices. Toward this end, the meter is of a special design and, due to its simple design which is therefore favorable as regards costs, is excellently suitable for said application. In particular the fastening by means of the end of the bearing pin projecting out of the meter contributes to the unproblematic use in any metering aerosol device.
This is an important advantage of the invention, as the inventive meter can be used with different inhalers, atomizers or similar metering aerosol devices without the known devices having to be essentially modified. This has the advantage that the metering aerosol devices have not once again to be subjected to tedious and costly tests regarding the clinical applicability and to approval procedures.
Furthermore, the inventive meter has small dimensions and, therefore, a handy system can be formed in a space-saving manner out of the meter together with the metering device.